Hexadecylphosphocholine is a known substance. In Pharmazie 37, 1982, pages 706-707, a lysing and fusogenic action is stated herefor. It has now been found that this compound also possesses an excellent anti-tumor action and, in comparison with homologous compounds, which are described in European Application 108 565, is characterized by the following surprising properties: whereas similar compounds with a shorter alkyl radical, such as for example tetradecylphosphocholine, show practically no anti-tumor action (for example, in vitro in the L1210 colony experiment or in vivo on the autochtanous methylnitrosourea-induced mammary carcinoma of the rat), those with a longer alkyl radical, such as for example octadecylphosphocholine, are admittedly anti-tumor effective but, at the same time, far too toxic and, therefore, not usable as medicaments. Thus, for example, in the case of a determination of the subacute toxicity during a treatment of 5 weeks at an anti-tumor effective daily dose of 77 .mu.mole/kg. rat orally, there was obtained an extremely high mortality which was 80% of all animals. Therefore, in spite of an anti-tumor action, the median survival time in comparison with the control was shortened by 72% in the case of octadecylphosphocholine-treated animals. In comparison thereto, in the case of hexadecylphosphocholine-treated animals, the mortality was lower by a half and, as a result of the absence of a chronic toxicity, it resulted in a highly significant increase of the median survival time of 26% in comparison with the controls.
Thus, within the homologous alkyl compounds, hexadecylphosphocholine occupies a surprising special position in that only hexadecylphosphocholine possesses a practically useful good anti-tumor action. Homologues with shorter alkyl radicals possess no or a much too low anti-tumor action. Homologues with longer alkyl radicals are admittedly effective against tumors but, at the same time, are much too toxic. Therefore, only hexadecylphosphocholine displays a sufficient anti-tumor action in non-toxic doses.
The invention concerns medicaments which contain hexadecylphosphocholine as active material and are especially suitable for the treatment of tumors sensitive to treatment with hexadecylphosphocholine.
Such medicaments possess an outstanding cytotoxic effectiveness which was demonstrated not only in vivo on chemically-induced mammary carcinoma of the rat but also in vitro on leukaemia cells in the cell culture. Furthermore, in a clinical pilot study in the case of female patients with mammary carcinomas, skin metastases were completely healed in the case of topical use.
It is known that hitherto no medicament for the treatment of tumors, especially of malignant tumors, was available which was satisfactory in all respects. Thus, for example, for the topical treatment of skin metastases in patients with metastasizing tumors, at present only 5-fluorouracil is available. Further developments of other cytostatics have hitherto not progressed to clinical maturity for this manner of administration. On the other hand, from a clinical point of view, such a concept of palliative therapeutic use is especially desirable since alternative concepts of treatment, such as surgical measures, radiation therapy and systemic chemotherapy, constitute comparatively aggressive therapy modalities. Furthermore, a considerable number of patients are available as potential treatment candidates for such a topical treatment. Thus, e.g. the proportion of mammary carcinoma patients who display a skin attack amounts to about 25 to 35%.
The prerequisite for topical treatment on the part of the active material to be used are compatibility to the skin, cytotoxic effectiveness against tumour cells and sufficiently deep penetration.